Fuel Pump Issues

Tue, 31 Aug 2021 09:35:49 GMT

go to see Welding Machine for Fuel Pump Issues

I'm having fuel problems with an NTC350BCIV Cummins.It's never been as powerful as I remember them being, and a week ago it almost left me walking back from Texas. Wouldn't run over 30mph.  Fuel starvation.I can't get a straight answer from Cummins as to proper fuel manifold pressure under different conditions.  Pump speed, etc.  As a matter of fact they won't give any information.This engine has the usual PTG fuel pump on it, with two test ports.  One port is for testing for fuel restrictions, and one port is loacated at the shutoff solenoid for testing output pressure.  Both fittings are Compucheck fittings designed for quick disconnect/connect.A restriction test is easy, it can't be in the high range.  I know these numbers.But I need the pressure numbers at the output side of the pump.I have another Cummins on hand in the yard.  But it needs batteries to fire it up.  I suppose I could test the output pressure on the good pump, and see what the other pump puts out, but I don't wanna buy a bunch of batteries   And I hate to lug all the batteries from the good truck over to start the non running truck.ANYBODY GOT THE PRESSURE NUMBERS ON THIS POS????"Any day above ground is a good day"http://www.farmersamm.com/
Reply:I think most of the older systems run around 45-5500psi at the injectors, I have no idea about that particular truck. I would call a truck shop, they should be able to pull the specs from their computers pretty quickly.
Reply:I have a book but its at my other place. I dont think you would need a lot of pressure because the injector builds its own pressure the pump just feeds them. Your other cummins will start with one small batterie unless it has a 24volt starter I do it all the time in hot weather. I will find book later today.
Reply:ThanksI came up with this, maybe it is ballpark, or not really stock.  Page down thru the posts to the guy with the K-1000, he's getting 125psi  http://www.thedieselgarage.com/forum...d.php?t=113097I think a lot of people don't realize the pump on this engine is not a high pressure pump, it's really a supply pump for the injectorw which develop actual high pressure with the plunger prior to injection.I also had a look in the Pittsburg Power Forum and came up with this http://www.pittsburghpower.com/suppo...c.php?f=7&t=95  A stock NTC350 produces 155psi fuel pressure at 18lbs boost according to this.See what you come up with"Any day above ground is a good day"http://www.farmersamm.com/
Reply:I'm seeing no change in performance when the anaroid is disconnected.  I think there would be a difference as the anaroid is a flow device actuated by intake manifold pressure (ie. at boost).I did put outside air pressure (20psi) to the AFC (anaroid) when it was disconnected, but saw no difference.  And a vacuum test showed the diphragm is not leaking  So, even if boost is low, the outside air source should have done something to performance   Possibly the piston is stuck in the bore??"Any day above ground is a good day"http://www.farmersamm.com/
Reply:My book which is a cummins manual refered to a some other book. I have worked on several 855 but never been into the pump. Maybe you need to put a button in it. I worked at a place that the drivers would do this. they had me pull the pumps and have them recalibrated the boss told drivers they would be caned if they cut pump tamper wirer.
Reply:Originally Posted by Old Doug the boss told drivers they would be caned
Reply:If it's the setup I think it is the output of the pump varies. The output pressure of the pump is what determines the amount of fuel that the injector pumps on each stroke. My problem is that it's been to long (28 years) since I was trained on those old systems and I can't remember the pressure range that it's supposed to put out.  Those old pressure timed systems are way different from any of the other systems modern or old alike. The injectors have a fixed displacement and the amount of input pressure from the pump on the side of the engine is used to vary the amount of fuel they inject with each stroke. Seems pretty impossible if you look at it from a physics stand point since diesel doesn't compress. But they did work and where cheaper to build than the other more complicated systems which made them popular.Last edited by irish fixit; 09-06-2012 at 09:56 PM.Millermatic 252XMT 304'sDynasty 280DXHypertherm PowerMax 1250Miller Trailblazer 302 EFIOptima PulserXR feeder and XR Edge gun and more athttp://members.dslextreme.com/users/waynecook/index.htm
Reply:Irish, I'm thinking 175psi +/- depending on pump code but my books also refer the reader to other publications that cover the pump specifics.MM200 w/Spoolmatic 1Syncrowave 180SDBobcat 225G Plus - LP/NGMUTT Suitcase WirefeederWC-1S/Spoolmatic 1HF-251D-1PakMaster 100XL '68 Red Face Code #6633 projectStar Jet 21-110Save Second Base!
Reply:I defer to you always.   Like I said it's been way to long since I've worked with those engines. We trained on them but never had any in the field to work on. When I got out I never worked around them that much.   I've definitely not got any of my old materials around to try and refer to any more. I'd already edited out my pressure reference before seeing your post since I was pretty sure it was wrong.Millermatic 252XMT 304'sDynasty 280DXHypertherm PowerMax 1250Miller Trailblazer 302 EFIOptima PulserXR feeder and XR Edge gun and more athttp://members.dslextreme.com/users/waynecook/index.htm
Reply:Well I'm not 100% on those general figures either as it's been more than 28 yrs for me.  Although I do still have the pressure gauge I used to use for checking.  Also used it for checking Allison pressures so it goes to 450psi.MM200 w/Spoolmatic 1Syncrowave 180SDBobcat 225G Plus - LP/NGMUTT Suitcase WirefeederWC-1S/Spoolmatic 1HF-251D-1PakMaster 100XL '68 Red Face Code #6633 projectStar Jet 21-110Save Second Base!
Reply:Well, here's the plan Gonna go get some batteries (I need a few for the old LN9000 anyways), and fire up the other truck that has the same engine.  I bought this truck for parts ($1200), and now I don't want to part it out I got these inbound http://www.ntxtools.com/network-tool...-TU-32-20.html  and http://www.ntxtools.com/network-tool...-TU-32-21.htmlTo make sure I'm talking apples and apples, I'll go to Cummins Quickserve Online and run the serial # on the other truck engine to make sure it's relatively identical.  I'll also be able to pull up a pump # from the site to see if the pumps are the same.  (Although calibration on either pump might vary a bit, I'll get a nice ballpark figure).  Remember all the pumps on these engines are the same, it's the buttons that vary as well as other metering devices.I'm betting on either a fuel line restriction on the suction side, bad AFC, or a clogged filter screen in the pump.  Either way, I would prefer gauging it instead of stabbing around in the dark.  It's more scientific For anyone interested in these systems here's a few links which explain the operation.http://www.waybuilder.net/sweethaven...Num=5&modNum=1http://www.liberatedmanuals.com/TM-55-4018-1.pdf  This download is a bit weird, it takes time, and sometimes you have to refresh the page.Now let's crunch the numbers.........................To test the pump it costs $275, which includes all new gaskets and seals and a cleaning.To rebuild the pump, if necessary, it runs the total up to $500So, for roughly $225 I get a set of gauges, and find out for myself whether the pump is the problem.  I'd hate to send the pump in, find out it's ok, and still have to root around for the problem elsewhere.  It's a gamble.The truck hasn't been on the road since I changed out the fuel filter (it had a new one previously installed about 4000mi ago) because of this  For all I know, the filter change might have done the trick, will find out when the tire is mounted.Strangest thing I've ever seen, the tire went flat, didn't blow out.  Might have been due to the low speed the truck was running on the return trip from Texas.  Musta been those FABULOUS TEXAS ROADS  "Any day above ground is a good day"http://www.farmersamm.com/
Reply:Are you certain it's fuel related? My Wife jumped a tooth on the timing belt on her little diesel TDI and it had similar problems... it would start and drive but top out about 20 mph. No power. I don't recall if it smoked... that was 10 years ago... but it must have. And you have plenty of air?
Reply:Samm,That referenced TM calls out in the 'troubleshooting' section for "Sudden loss of power" to check for fuel filter problem (plugged up, replace filter), suction line restriction (old collapsed rubber fuel line, replace line), or a suction air leak (also comes with hard starting, check all suction lines and fittings and ensure lines are in good shape and all fittings are properly tight, also bleed air out of system, see TM).Quick google-fu also turns up http://www.liberatedmanuals.com/TM-5-2815-233-14.pdfwhich lists under "Low power or Loss of power"- air intake prob (check/clean air filter)- high exhaust backpressure (something 'stuck' in the exhaust line?)- air leaks between air cleaner and engine- turbo problem- poor quality fuel- air leak in fuel suction line- restricted fuel line- fuel leaks- plugged injector(s)- gear problem on the fuel pump- throttle link adjustment- overfilled crankcase- ASA/AFC plugged or leak- internal engine problems (valves, gaskets, rings, etc)Some web references indicate that the fuel pump pressure on a test stand is around 170-180 psi.  Actual pressure on the truck varies with power/rpm (as you know).Also, possible problem with the spring(s) inside the fuel pump?  The best laid schemes ... Gang oft agley ...
Reply:a few years ago,the cummins on my case backhoe lost most of it's power.changing filters didn't help,so i crawled under it thinking i would drain the fuel systen to check for dirt or water. found that some previous owner had cut the fuel line and inserted an in-line filter ---wtf !!! didn't he notice the two large filters on the side of the engine ? mickey mouse filter was clogged. patched the fuel line and all was well.miller thunderbolt 250vlincoln square wave tig 175 prolincoln idealarc mig sp250everlast tig 210EXTeverlast power plasma 50chicago electric (hf) 130 tig/90 arcchicago electric 90 amp flux wire3 sets oxy/acet
Reply:Samm how long did this truck set before you started running it?  When you changed the fuel filter did it have any larger black particles in it? What about smoke? Is there any? Color? Only on a pull? The ultra low sulfur has a scrubbing agent in it that is hard on the hose liners. It also grows algae better than the old fuels."Liberalism is a mental disorder" Dr. Savage
Replyittle update..............................I'm still waiting on test gaugesDO NOT ORDER TOOLS FROM THIS COMPANY  http://www.ntxtools.com/Ordered the tools on 9/7, and still hadn't even shipped by 9/22 They lied to me, and said the order was in "maintenance" phase ie. on the brink of shipment, and couldn't be cancelled, F YOU says me  I canceled my credit card so it couldn't be billed, and ordered the stuff from another company.  A bit higher, but IN STOCK AND SHIPPED SAME DAY.  It gets here Thursday.  So that's about 3 weeks the truck's been down In the meantime I've had time to replace a bad rear axle seal, and send out the cab tilt cylinder for rebuilding (5-7 day turnaround , UNLESS YOU DOUBLE THE HOURLY SERVICE RATE, THEN YOU GET IT BACK IN 3 DAYS)  Another F YOU was in order Think this is funny, I'm thinking seriously about getting this sweet little OLD Ford Louisville to add to my woes I swear it's a Republican conspiracy "Any day above ground is a good day"http://www.farmersamm.com/
Reply:Oh yeah, I got the tracking order from Hands ON Tools the very day it was shipped.  Good place to do business"Any day above ground is a good day"http://www.farmersamm.com/
Reply:from what i know of the cummins PT (Pressure Time) injection system on the big cam engines 170-180 is the stock pressure and  225 is on the real high side for a hard pull under heavy load with a built up cummins.   And for a good reference 180 PSI of fuel pressure will put 3,000Lb shock load on the injector push rods.    I take it your truck is a basic fleet spec truck with no boost or pyrometer gages?      If it is and your going to be running this truck i would say they would be a good investment.    They can tell you alot about whats going on in the cylinders.   Also many have installed a liquid filled fuel rail pressure gage to actually verify that the pump is making pressure ON the truck.   Some pumps make great pressure on the stand but can loose up to 30 PSI on the truck.There are over 6,000 different CPL's for cummins engines so comparing one to another is really just a rough guess estimate but will get you in the ballpark.The FIRST thing i would look at is the fuel suction hoses from the fuel tank.    They are only good for about 10 years max.      chaging them out with fresh areoquip lines would be a cheep and easy thing to do FIRST.   you would be amazed the amount of tucks that are "poor runners" that have internally collapsed fuel suction lines.Last edited by Dualie; 09-26-2012 at 02:20 AM.Vantage 500's LN-25's, VI-400's, cobramatics, Miller migs, synch 350 LX, Powcon inverters, XMT's, 250 Ton Acurrpress 12' brake, 1/4" 10' Atlantic shear,Koikie plasma table W/ esab plasmas. marvel & hyd-mech saws, pirrana & metal muncher punches.
Reply:I was hoping you all were right, and it would be a restriction or air leak issue.Gauged it (finally) yesterday.0 pressure at idle (not enough to move the gauge anyways)150psi on a "snap test", back to around 15 momentarily when the governor unloads and dumps fuel back to the gear pump/return, then back to 0 at idle.Vacuum read no higher than 2 inches at any throttle setting.  There are no restrictions, or the gear pump or some other internal is malfunctioning.  I'll pressure up the system to make sure it's not an air leak on the intake lines.  It should pull at least 4in vacuum with a good filter and clear lines.So.................it's off the motor I guess, and off to the rebuilder if the air leak test proves negative.   $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$Lesee now............  About an estimated 300 bucks to rebuild the lift cylincer, 110 for the "new" tire, 50 bucks for a new seal on the axle end, and as high as 1500 for the pump if any hard parts are needed.  (500 for a base repair).  With luck they might have an exchange pump on the shelf.So I suppose it's still cheaper than truck payments   But it doesn't take the sting out of it "Any day above ground is a good day"http://www.farmersamm.com/
Reply:Not being too familiar with the system, I need to determine if the return might be to blame.  I'm not sure if there are check valves at the head or not.  There is a check valve at the pump to allow fuel to run from the gear pump to the return line for cooling.  So far I haven't read up on the schematic up on the head, and how the rail feeds/returns fuel.Good breakfast reading I guess"Any day above ground is a good day"http://www.farmersamm.com/
Reply:If my memory serves me right theres only an orifice.   You could get a big boost in power by putting vice grips on the return line in the early PT systems.   after a while cummins engineers figured it out and designed that flaw out of the systemwhats your boost pressure under load?Vantage 500's LN-25's, VI-400's, cobramatics, Miller migs, synch 350 LX, Powcon inverters, XMT's, 250 Ton Acurrpress 12' brake, 1/4" 10' Atlantic shear,Koikie plasma table W/ esab plasmas. marvel & hyd-mech saws, pirrana & metal muncher punches.
Reply:The new lift cylinder arrived about 2 days ago, and now it's time to pull the fuel pump to exchange for a rebuilt.Bleeding the system after installing the cylinder went well, all things considered (had to do it without my helper  he's got no thumbs )Cylinder inAnd up she goesHenry was beside himself with excitementLeast now I can get to the pump"Any day above ground is a good day"http://www.farmersamm.com/
Reply:And so it goes............The pump is held in place with 12pt capscrews, ONE OF WHICH CAN'T BE REACHED WITH ANY TOOLS KNOWN TO MAN Gotta make do, so.......head to the parts store, and pick up a sacrificial wrench, then hit it with the hot wrench to "amend" the shape  YOU WILL COMPLY!!!!!!!!!!!!!!!!!!!!!!!Now I got something I can work withFits the bill nicely, and the pump's sitting in back of the pickup for a ride to Tulsa in the morning.LET THIS BE A LESSON TO THE PLASMA HEADS.  A PLASMA AS YOUR FIRST CUTTING TOOL IS NOT A GOOD IDEA.  THE O/A TORCH IS THE MOST VERSATILE CUTTING/BENDING/SWEATING/SHAPING TOOL ON THE PLANET(Carry on )"Any day above ground is a good day"http://www.farmersamm.com/
Reply:Akshulllly......there is such a thing as a Half Moon Wrench, and S Type Wrenches, that will work on this kind of thing, but I didn't have any on hand.  They be coming from Amazon though."Any day above ground is a good day"http://www.farmersamm.com/Now you have a post for the "home made tool" thread there Samm. I agree about the versitility of the OA torch. I've made up a few wrenches like this in the past as well when I had no other option. Glad to see you got it out and hopefully will be back on the road soon..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:Originally Posted by farmersammAkshulllly......there is such a thing as a Half Moon Wrench, and S Type Wrenches, that will work on this kind of thing, but I didn't have any on hand.  They be coming from Amazon though.
Reply:hey samm   [ame]http://www.amazon.com/GearWrench-9850-Metric-Double-Ratcheting/dp/B000HBAICW[/ame]   ratcheting half-moonsmiller thunderbolt 250vlincoln square wave tig 175 prolincoln idealarc mig sp250everlast tig 210EXTeverlast power plasma 50chicago electric (hf) 130 tig/90 arcchicago electric 90 amp flux wire3 sets oxy/acet
Reply:So samm what ever happened to your truck? did you get to the bottom of the power problems or what?Miller thunderbolt 250Decastar 135ERecovering tool-o-holic ESAB OAI have been interested or involved in Electrical, Fire Alarm, Auto, Marine, Welding, Electronics ETC to name a just a few. So YES you can own too many tools.
Reply:You are going to need to make one of those mutated wrenches out of a 1/2 inch if you ever plan to do any work on the water pump, governor, or fuel pump on your 6-71 without pulling the blower.
Reply:But, I recently worked on a boat that had a Cummins NH220 engine.  Unusual unit because there was no fuel rack.  I assumed that low pressure fuel from the pump controlled the stroke of the injector.  It may have been confirmed when the owner of the boat closed a valve on the return side and had the engine run away.  You're going to have a wide range of fuel pressures based on the load you place on the engine so there probably is no set number and it will be difficult to test without putting the truck on a dyno.